This invention relates generally to the building construction industry, and more particularly to a device adapted for securely maintaining electrical conductors (e.g., ROMEX wiring) at a predetermined distance from a wall.
In constructing or rehabbing buildings, homes, and the like, studs are secured vertically to define a frame for walls of the building. Electrical conductors, such as wiring, are secured to the studs to provide electricity and other utilities throughout the building. Plasterboard (drywall) is thereafter secured to the studs with screws, nails or other fasteners to form the walls of the building. Typically, nail or screw guns are used to rapidly and forcefully drive fasteners into the studs. Because the studs are behind the drywall, and because the fasteners are installed rapidly with a gun, it is not uncommon for a fastener to miss the stud during the installation process. This can damage an electrical conductor behind the wall. Electrical wiring for homes is typically 120 or 240 volts, and for commercial buildings, the voltages can be significantly higher. Thus, an installer is exposed to the risk of a severe electrical shock. A damaged wire may also create a dangerous fire hazard.
Further, to decorate a completed building, pictures, clocks, lighting fixtures and other items are typically hung on walls using fasteners such as nails and screws. Since the electrical conductors behind these walls are hidden from view, the person hanging these items is exposed to the same hazards described above.
For these reasons, in 1990, the National Electrical Code (NEC) was amended to require that electrical conductors be secured at least one-and-one-quarter inches (11/4") behind the wall. Even in the absence of such regulation, it is, of course, prudent to secure electrical conductors a sufficient distance behind the wall to ensure that a nail or screw does not go through the wall into a conductor, thereby causing injury and/or creating a fire hazard.
To address this problem and to conform with the NEC, devices were developed in an effort to securely and uniformly maintain electrical conductors a safe distance behind a wall. An example of such a device is shown in U.S. Pat. No. 5,141,185 (the '185 patent). The '185 patent discloses an L-shaped bracket, one arm of which is adapted to be bent back with respect to the other arm of the bracket to secure conductors therebetween. The bracket is made out of a bendable, substantially non-resilient metal which can be crimped, if necessary, to hold the conductors between the arms of the bracket.
There are several disadvantages associated with the '185 patent. While the device disclosed therein maintains the conductors a desired distance from the wall, the device is not suited for tightly gripping or clamping the conductors. As a result, the conductors tend to slide or slip vertically within the bracket, which causes the conductors to buckle toward the wall in areas where the conductors are not held by the bracket. This problem is particularly acute when the device is holding several conductors of varying diameter and size, as shown in FIG. 12 of the '185 patent. In this situation, smaller diameter conductors adjacent larger diameter conductors are especially prone to slip, which can result in code violation. Another problem associated with the device of the '185 patent is that the device is made out of a bendable but substantially non-resilient metal. Thus, if the device is inadvertently bent out of position during the installation process, the conductors held by the device will not be properly positioned with respect to the wall according to NEC standards. Yet another problem is that the device sometimes requires crimping the arm of the bracket around individual conductors, which can be cumbersome and time consuming.
Another type of device is made out of a stiff, plastic. The device has a plurality of individual slots of a predetermined width, formed by adjacent arms. The arms are resiliently biased to a closed position. A conductor can be inserted into a slot by pulling an arm to open a corresponding slot. After the conductor is inserted into the slot, the arm is released to return to its biased closed position, thereby holding the conductor within the slot. Such a device suffers from the slippage problem described above to an even greater extent than the '185 patent because the slots are of predetermined width and thus are not adapted for tightly gripping most conductors. Moreover, because the arms of the device are made out of plastic, the arms cannot be crimped to apply a compressive force to the conductor.